Implement force detach volume

1.what is the problem?
In Trio2o, when a volume is in a stuck 'attaching' or 'detaching', Pod
can not detaching it by nova-apigw 'detach volume', so that this volume can
not reuse by ohther Pod. In addition, it may cause un-synchronization between
the Cinder database and the backend storage.
   There is an user case in nova[1]. It may also occur on a trio2o Pod.
We don't need to worry about its security, because the Cinder api
'os-force-detach' is for safe cleanup. More user case and information
about 'force detach' in this document[2].

2.what is the solution to the problem?
We use Cinder api "os-force-detach" to detach it.

3. What the features need to be implemented to the Trio2o
   to realize the solution?
Implement the force detach server action.

[1] https://blueprints.launchpad.net/nova/+spec/add-force-detach-to-nova
[2] https://github.com/openstack/cinder-specs/blob/master/specs/liberty/implement-force-detach-for-safe-cleanup.rst

Change-Id: Iea15c4d9ce469fb640e7e98c1859a18fe12ce7f3

trio2o/cinder_apigw/controllers/volume_actions.py

@@ -42,7 +42,8 @@ class VolumeActionController(rest.RestController):
             'os-reset_status': self._reset_status,
             'os-set_image_metadata': self._set_image_metadata,
             'os-unset_image_metadata': self._unset_image_metadata,
-            'os-show_image_metadata': self._show_image_metadata
+            'os-show_image_metadata': self._show_image_metadata,
+            'os-force_detach': self._force_detach
         }
 
     def _get_client(self, pod_name=constants.TOP):
@@ -104,6 +105,15 @@ class VolumeActionController(rest.RestController):
         return self._action(context, pod_name, 'os-extend',
                             {'new_size': new_size})
 
+    def _force_detach(self, context, pod_name, kw):
+        """Forces a volume to detach
+
+        :param pod_name: the bottom pod name.
+        :param kw: request body.
+        """
+        body = kw['os-force_detach']
+        return self._action(context, pod_name, 'os-force_detach', body)
+
     def _reset_status(self, context, pod_name, kw):
         """Update the provided volume with the provided state.
 

trio2o/tests/unit/cinder_apigw/controllers/test_volume_actions.py

@@ -196,6 +196,27 @@ class VolumeActionTest(unittest.TestCase):
         mock_action.assert_called_once_with(url, body=body)
         self.assertEqual(202, res.status)
 
+    @patch.object(pecan, 'response', new=FakeResponse)
+    @patch.object(HTTPClient, 'post')
+    @patch.object(context, 'extract_context_from_environ')
+    def test_force_detach_volume_action(self, mock_context, mock_action):
+        mock_context.return_value = self.context
+        mock_action.return_value = (FakeResponse(202), None)
+
+        t_pod, b_pods = self._prepare_pod()
+        self._prepare_pod_service(b_pods[0]['pod_id'], constants.ST_CINDER)
+        t_volume_id = self._prepare_volume(b_pods[0])
+        t_server_id = self._prepare_server(b_pods[0])
+        self.controller.volume_id = t_volume_id
+        body = {"os-force_detach": {
+            "attachment_id": t_server_id,
+            "connector": {
+                "initiator": "iqn.2012-07.org.fake:01"}}}
+        res = self.controller.post(**body)
+        url = '/volumes/%s/action' % t_volume_id
+        mock_action.assert_called_once_with(url, body=body)
+        self.assertEqual(202, res.status)
+
     @patch.object(pecan, 'response', new=FakeResponse)
     @patch.object(HTTPClient, 'post')
     @patch.object(context, 'extract_context_from_environ')